Polynomial Analysis 6Ec726
1. **State the problem:**
We are given the polynomial function $$f(x) = -x^2 (x+4)(x+2)$$ and its expanded form $$-x^4 - 6x^3 - 8x^2$$.
2. **Write the polynomial in standard form:**
The polynomial is already expanded and written in standard form as $$-x^4 - 6x^3 - 8x^2$$.
3. **Degree of the polynomial:**
The degree is the highest power of $$x$$, which is $$4$$.
4. **Leading coefficient:**
The coefficient of the term with the highest degree $$x^4$$ is $$-1$$.
5. **End behavior:**
For a polynomial $$ax^n$$ where $$n$$ is even and $$a < 0$$, as $$x \to \infty$$, $$f(x) \to -\infty$$ and as $$x \to -\infty$$, $$f(x) \to -\infty$$.
But here, since degree is 4 (even) and leading coefficient is negative, the end behavior is:
- As $$x \to \infty$$, $$f(x) \to -\infty$$
- As $$x \to -\infty$$, $$f(x) \to -\infty$$
(Note: The user states $$f(x) \to \infty$$ as $$x \to -\infty$$, which is incorrect for even degree with negative leading coefficient.)
6. **Turning points:**
The polynomial has 3 turning points as given.
7. **Approximate coordinates of maxima:**
At approximately $$(-3.5, 10)$$ and $$(0, 0)$$.
8. **Approximate coordinates of minimum:**
At approximately $$(-1.25, -3)$$.
9. **Intervals where the function increases:**
$$(-\infty, -3)$$ and $$(-1.5, 0)$$.
10. **Intervals where the function decreases:**
$$(-3, -1.5)$$ and $$(0, \infty)$$.
**Final answers:**
- Standard form: $$-x^4 - 6x^3 - 8x^2$$
- Degree: $$4$$
- Leading coefficient: $$-1$$
- End behavior: as $$x \to \infty, f(x) \to -\infty$$; as $$x \to -\infty, f(x) \to -\infty$$
- Turning points: $$3$$
- Maxima: $$(-3.5, 10), (0, 0)$$
- Minimum: $$(-1.25, -3)$$
- Increasing intervals: $$(-\infty, -3), (-1.5, 0)$$
- Decreasing intervals: $$(-3, -1.5), (0, \infty)$$